Rotary catheter drive unit containing seal-sets

ABSTRACT

A rotary catheter drive unit containing a motor and a seal-set, an output shaft of the motor being power transmittingly connected to a flexible shaft that is rotatably disposed through the seal-set, the seal-set comprising a bearing and an adjacent seal defining a first and a second concentric bores, respectively, the first bore being slightly larger than a diameter of the shaft so that it rotatably and accurately supports the shaft, the second bore being slightly smaller than the diameter so that it seals around the shaft, the bearing aligning the shaft, so that it is concentric with the second bore, by deflecting the shaft to compensate for eccentricity and misalignment of the second bore relative to the output shaft of the motor.

CROSS REFERENCE TO RELATED APPLICATIONS

Priority is claimed based on:

U.S. patent application Ser. No. 13/695,232 by Shiber, entitled “ROTARYCATHETER FOR REMOVING OBSTRUCTIONS FROM BODILY VESSELS”, filed on Jan.8, 2013, which claims priority from Pat. Appl. PCT/US2011/031197 filedon Apr. 5, 2011 by Shiber, and entitled “ROTARY CATHETER FOR REMOVINGOBSTRUCTIONS FROM BODILY VESSELS”, which further claims priority fromU.S. Provisional Pat. Appl. Ser. No. 61/343,796, filed on May 4, 2010 byShiber and entitled “THROMBECTOMY AND ATHERECTOMY CATHETER” and U.S.Provisional Pat. Appl. 61/461,263 filed on Jan. 14, 2011 by Shiber andentitled “CATHETER FOR THROMBECTOMY AND ATHERECTOMY”; and

U.S. patent application Ser. No. 14/238,983, filed on Feb. 14, 2014, byShiber, entitled “ADAPTIVE ROTARY CATHETER FOR OPENING OBSTRUCTED BLOODVESSELS”, which claims priority from Pat. Appl. PCT/US2012/050759 filedon Aug. 14, 2012 by Shiber, and entitled “ADAPTIVE ROTARY CATHETER FORREMOVING OBSTRUCTIONS FROM BODILY VESSELS”, which further claimspriority from U.S. Provisional Pat. Appl. Ser. No. 61/575,289, filed onAug. 17, 2011 by Shiber and entitled “ROTARY CATHETER FOR BREAKING DOWNAND ASPIRATING OBSTRUCTIONS FROM BODILY VESSELS” and U.S. ProvisionalPat. Appl. 61/686,864 filed on Apr. 13, 2012 by Shiber and entitled“ROTARY CATHETER FOR OPENING OBSTRUCTED BODILY VESSELS”; as well as

U.S. Provisional Pat. Appl. 61/998,138 filed on Jun. 18, 2014 by Shiberand entitled “PHARMACEUTICAL-MECHANICAL SYSTEM FOR OPENING OBSTRUCTEDBLOOD VESSELS”; all the disclosures contained in the above patentapplications and provisional patent applications are incorporated hereinby reference in their entirety.

FIELD OF THE INVENTION

This application relates to catheters and methods using mechanical andpharmaceutical means for opening partially and totally obstructed bodilyvessels of varying diameters such as blood vessels.

BACKGROUND OF THE INVENTION

Prior art mechanical devices are often limited to treating a narrowrange of vessel diameters and a certain type of obstruction. However,the diameter and the nature of the obstruction often varies along thediseased vessel, requiring multiple sizes and different kinds of priorart devices in a single clinical case. Furthermore, each of such priorart devices can be slow, traumatic and expensive. For example, a numberof prior art devices comprise an abrasive tip with a spherical crosssection, mounted on a rotating shaft to grind the obstructions to verysmall particles that can pass through the capillary blood vessels. Dueto the small size of the particles, these devices have to be rotated athigh speeds (e.g., 200,000 revolutions per minute) to grind the entireobstruction material in a reasonable time. In some of these devices, thetip is eccentrically mounted on the shaft and some of these devices useaspiration to try to remove the particles. However, as the abrasive tipof these devices grinds through a small vessel or through a hardobstruction material, even if the tip is mounted eccentrically on theshaft, it is forced to rotate in an opening that is not larger than thetip, which the tip essentially blocks. This prevents aspiration andcooling fluid or drugs from reaching the sides and the distal end of thetip, which may quickly cause thermal injury and/or perforation of thevessel wall.

A different commonly used method to open obstructed blood vesselsconsists of bringing clot-dissolving drugs (e.g., thrombolytic drugssuch as streptokinase, urokinase, tPA and the like) into contact withthe obstruction. However such drugs may take a long time, especially inthe case of a long obstruction. Thus, catheters, which deliver and mixthe drug with the obstruction material to accelerate the process, areavailable (e.g., Trellis System sold by Covidien Co., Mansfield, Mass.),but such systems are relatively cumbersome, expensive and addressprimarily soft obstructions.

SUMMARY OF THE INVENTION

By way of comparison, an embodiment of the present invention has anasymmetric narrow tip with sides that are designed to bluntly impact theobstruction to break the obstruction mechanically. The narrow tip alsodefines passages that deliver cooling/lubricating fluid and drugs to theimpact site and allows the dual mechanical and pharmaceutical co-actionto quickly break down the obstruction to particles. The same passagesallow the tube to aspirate fluid laden with particles.

The embodiment comprises a motor-driven flexible hollow shaft whosedistal portion is preferably made of a spiraled wire and a tip affixedto its distal end. The flexible hollow shaft is rotatably disposed in aflexible tube and a fluid channel is defined between an internaldiameter of the flexible tube and an external diameter of the hollowshaft. The distal portion of the flexible hollow shaft extends out ofand is free to move radially relative to the tube, enabling the fluidchannel to ingest particles which are smaller than a difference betweenthe internal and external diameters. Relative motion between theradially moving and rotating flexible hollow shaft and the flexible tubeeases movement of the particles through the fluid channel and impedesthe particles from clogging the fluid channel. A tip made of a hardmaterial, such as stainless steel having a narrowed cross section (ascompared to a round cross section), is affixed to a distal end of thehollow shaft. The tip has a rounded atraumatic (i.e., less likely toinjure a wall of the vessel) distal end which defines a bore adapted tofit over a guidewire and the flexible hollow shaft and the tip arerotatable and slideable over the guidewire. The tip, which is extendedout of a distal end of the flexible tube to enhance its engagement withthe obstruction material, has a first and second sides. The first sideis adapted to bluntly impact the obstruction material when the tiprotates in a first direction and vice versa. The tip also has a base andan opposing smooth crown that is offset away from a longitudinal axis ofthe flexible hollow shaft further than the base is offset away from thelongitudinal axis, enlarging the area that the tip can sweep whenrotating in a larger vessel.

A distance between the sides is smaller than the distance between thecrown and the base, leaving open aspiration passageways along the sideseven when the tip is a small vessel or when it is tunneling through ahard obstruction. The passages allow fluid (e.g., saline, thrombolyticand other drugs as well as blood) to irrigate and lubricate theimpact-site and bring the drugs in contact with the obstruction's newsurfaces as soon as they are created by the rotating tip in order tocombine the chemical effect with the tip's mechanical effect. Themaintained fluid supply through the passages also prevents theimpact-site from becoming dry and overheated by the mechanical action ofthe rotating tip. The passages also carry the particles from the impactsite as well as the area surrounding the distal end of the rotating tip,as they are aspirated into the tube.

Total occlusions often prevent advancement of a guidewire and therebyprevent the delivery of percutaneous trans-catheter treatment, forcing apatient to undergo a more formidable bypass surgery. With the presentinvention, upon encountering a total obstruction that cannot be crossedwith the guidewire, the rotary catheter can be advanced to theobstruction and the guidewire can be withdrawn proximally past the tip,adapting the system to cross a total occlusion. As the tip is rotated,it's smooth crown atraumatically slides against the vessel's wall anddisplaces the distal end of the tip away from the wall, directing thetip to tunnel through the obstruction. Once the obstruction is crossed,the guidewire can be advanced distally past the tip to provide guidanceand support to the rotary catheter.

The rotary catheter can be inserted into the vessel directly, e.g., whenaccess to a vessel is gained surgically, or through the skin via anintroducer. The introducer can also be used to inject fluids, such assaline, with drugs and radiopaque contrast agent into the vessel, which,together with blood, keeps the obstruction particles suspended so thatthey can be readily aspirated. An optional guiding catheter can be usedwhen the rotary catheter has to be guided further into the vessel. Theguiding catheter can incorporate a proximal embolic barrier fortemporarily blocking flow through the vessel, while the rotary cathetermacerates and aspirates the obstruction material, thereby reducing thelikelihood of releasing particles and drugs downstream. A distal embolicprotection device can also be employed for the same purpose and, whenthe rotary catheter is used in a limb, an external pressure cuff can beutilized to temporarily stop circulation in the affected limb.

The flexible hollow shaft that is disposed in the flexible tube detersthe flexible tube from kinking (i.e., diametrically collapsing) andprevents the flexible hollow shaft and tube from being sharply bent atthe point in which they are connected to the housing. Their radii ofbending is limited by a radius of curvature of a wall of a depressiondefined by the surrounding housing. The rotary catheter can bemanufactured in varying lengths and diameters to reach and treatdifferent anatomical locations and different forms of obstructions, aswell as to suit users' preferences.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a motorized rotary catheter, according to the presentinvention, with a tip extended out of a distal end of the flexible tube;

FIG. 1 a shows the motorized rotary catheter with the distal end of itsflexible tube slid close to the tip to reduce a gap between them andimpede an edge of the flexible tube from engaging with a wall of thevessel while the rotary catheter is advanced distally in the vesseltowards an obstruction (“distal” or “distally” refers to a location or adirection further into the vessel and “proximal” or “proximally” meansthe opposite);

FIG. 1 b shows enlargement of a rotary seal-set (as explained below);

FIG. 1 c shows cross-sectional enlargement of a connection between aferrule and flexible tube viewed on a plane 1 c-1 c marked on FIG. 1 a;

FIG. 1 d is cross-sectional view of a proximal seal mechanism shown inan open-position (the proximal seal is shown, as a part of theembodiment depicted in FIG. 1, in a closed-position);

FIG. 1 e is cross-sectional view of an alternative proximal sealmechanism shown in an open-position.

FIG. 2 shows an enlargement of a region marked 2 on FIG. 1, where thevessel is totally occluded and the guidewire withdrawn proximally beyondthe distal end preparatory to the tip crossing the obstruction;

FIG. 3 shows a distal end of the tip viewed on plane 3-3 marked on FIG.2;

FIG. 3 a shows a distal end of a modified tip;

FIGS. 4, 5 and 6 show examples of cross sections of flattened wires thatcan be used to wind a spiraled wire;

FIG. 7 shows an enlargement of an optional welded connection between aflexible hollow shaft portion and spiraled wire;

FIG. 8 shows an enlarged cross section of the tip area;

FIG. 8 a shows a perspective view of the tip;

FIG. 8 b shows a perspective illustration of the tip;

FIG. 9 shows a further enlargement of the distal end of the tip;

FIG. 10 shows an overview of a modified rotary catheter, wherein theflexible tube can be optionally moved distally over the tip to shield itas shown in FIG. 10 a;

FIG. 10 b shows an end view of the rotary catheter as viewed on a plane10 b-10 b marked on FIG. 10 a;

FIG. 11 shows a further modification of the rotary catheter, wherein thedistal end of the flexible tube is terminated diagonally;

FIG. 12 shows a further modification of the rotary catheter, wherein theshape of the distal end of the flexible tube resembles a scoop of agarden trowel;

FIG. 13 shows an further modification of the rotary catheter, whereinthe sheath resembles a scoop of a garden trowel with a thickened bottom;

FIG. 14 shows a further modification of the rotary catheter, wherein adistal end section of the spiraled wire that is extended out of thedistal end of the flexible tube is straightened by a guidewire that isdisposed through it. The spiraled wire is pre-formed to automaticallyassume a curved shape in response to the guidewire being removed;

FIG. 15 shows the rotary catheter as viewed in the direction of arrow15′ marked on FIG. 14, wherein the first side of the tip is inclined sothat it propels fluid and particles of the obstruction proximally whenthe tip rotates in a first direction;

FIG. 16 is cross sectional view of the tip, along a plane 16-16 markedon FIG. 14, which shows a further modification of the tip, wherein anoffset of the base is minimized and an offset of the crown is enhanced.

FIG. 17 shows the modified rotary catheter of FIG. 14 wherein the distalend section of the spiraled wire automatically assumed a curved shapeand increased the offset of the tip in the absence of the guidewire;

FIG. 18 shows the rotary catheter viewed in the direction of arrow 18′marked on FIG. 17, where a distal end section of the flexible hollowshaft is extended out of the distal end of the flexible tube and ispre-formed to automatically incline the tip, in response to theguidewire being withdrawn from within the distal end section of thehollow shaft, so that it propels fluid and particles of the obstructionproximally when it rotates in a first direction

The middle portions of the embodiments shown in FIGS. 1, 1 a, 10, 10 a,11, and 12 have been represented by phantom lines due to spacelimitations on the drawing sheets.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows a motorized rotary catheter 10, according to the presentinvention, for opening an obstruction 11 (e.g., blood clot; atheroma) ina bodily vessel 12 (e.g., a blood vessel).

The rotary catheter 10 comprises a motor-driven flexible hollow shaft14, rotatably disposed in a flexible tube 13 that is preferably made ofthin plastic material. A proximal portion 16 of the flexible hollowshaft is preferably a thin-walled tube and a distal portion of theflexible hollow shaft 17 is preferably made of a spiraled wire. The wirethat is used to wind the spiraled wire preferably has a flattenedcross-section (such a cross section can be obtained by taking a standardround wire and running it between rollers that squeeze and flatten it,please note FIGS. 4-6). The flexible hollow shaft portions 16 and 17 arepreferably made of metal (e.g., stainless steel; Nitinol) and areconnected together, for example, by a circumferential weld 19 (pleasenote FIG. 1) or by two circumferential welds 24 and 25 and a reinforcingsleeve 30 (please note FIG. 7.)

A stainless steel tip 20 is affixed by a laser weld 21 to a distal endof the spiraled wire (please note FIG. 9) so that the flexible hollowshaft 14 and the tip 20 are rotatable and slideable over a guidewire 15.The weld 21 is at a point along the spiraled wire that is nested insidethe tip where the weld is subjected primarily to shearing loads but isotherwise protected. The tip has a first side 22 for impacting theobstruction as the flexible hollow shaft is rotated in a first direction40. A second side 24 can be used to impact the obstruction if theflexible hollow shaft is rotated in a second direction 41 (please noteFIG. 3.)

The tip also has a base 26 and an opposing crown 27 that is adapted toatraumatically slide against a wall of the vessel without injuring it.The tip 20 is asymmetrical, i.e., an offset 89 of its crown is largerthan an offset of its base 88. “Offset” refers hereinafter to a distancefrom the longitudinal axis 28 of the spiraled wire 17. The sum ofoffsets 88 and 89 equals to the height of the blade 90 and the offset 89is also the tip's “effective radius” i.e., one half of its “effectivediameter” 100. As the tip rotates around the axis 28, the crown slidesalong its surroundings while the side of the tip impacts whatever iswithin its effective diameter marked with a phantom line 29 and, asillustrated in FIG. 3, the resulting tunnel is substantially larger thana tunnel marked with an interrupted line 35 that a hypotheticalsymmetrical tip of equal height (i.e. offset 88 equals offset 89) wouldhave opened, however, it should be understood that above discussion ismeant to explain the concept of the asymmetrical tip and the actualcross-sectional area of the tunnel that the tip 20 opens may increasedue to, for example, dynamic forces affecting the tip (e.g., centrifugalforce) or the opening may decrease when, for example, the tip operatesin a smaller vessel or when it tunnels through a hard obstruction.

The tips narrowed cross-section with a width 91 that is smaller than itsheight 90 reduces the size and circumference of the cross-sectionrelative to a round tip whose diameter equals the height. This smallercircumference requires a smaller opening in the wall of the vessel forinserting the tip into the vessel. The narrowed cross-section alsoenhances the tip's ability to fit into a narrow opening in a hardobstruction and, as the tip rotates, to apply leverage in order to widenthe opening. The tip's narrowed cross-section also leaves openpassageways 22′ and 24′ along its sides 22 and 24, respectively. Thesepassageways enable aspiration from the distal end of the flexible tube13 to reach particles that are distal to the tip even when the tip isoperating in a small vessel or tunnel with a diameter as small as theheight 90. As the particles and fluid in which they are suspended passthrough passageways 22′ and 24′, over the rotating tip, they becomefurther macerated and are readily aspirated through the tube into asyringe 37 as discussed below.

A distal rounded end 36 of the tip 20 covers a distal end of thespiraled wire 39 and defines a bore 18 (please note FIGS. 2, 8 and 9)which rotatably and slideably fits over the guidewire, enabling theguidewire to support and guide the tip. A close fit between bore 18 andthe guidewire restricts blood flow through the bore 18 and the amount offibers and residue that enters through the bore 18 and may depositaround the guidewire.

As shown in FIG. 1 the flexible tube 13 is affixed (e.g., bonded and/orpress fitted) and radially supported internally by a ferrule 86, to astrain relief 83 which is affixed to a cylinder 42 which also houses aseal 43. The outer periphery of the seal 43 is tightly pressed by abushing 44 against a circular ridge 49 forming a peripheral static seal.The ridge is shown in the enlarged view FIG. 1 b. A bore 44′, defined bythe bushing, acts as a bearing, which offsets the flexible hollow shaftportion 16 to the extent that is needed to concentrically align relativeto a bore 43′, which is formed through the seal 43. Such a combinationof a seal and an adjacent concentric bearing are referred to hereinafteras a “seal-set”. This alignment on the one hand nulls the effect of thecumulative eccentricities and production tolerances contributed by partsnumbers 42, 45, 50, 51, 83 and the flexible hollow shaft portion 16, andreduces the interference fit needed between the bore 43′ and theflexible hollow shaft portion 16 to maintain a rotary seal between them.This alignment thereby reduces frictional power loss in the seal.Additionally, it also eases the tolerances that the parts 42, 45, 50, 51and flexible hollow shaft portion 16 have to be manufactured to andthereby lowers the manufacturing costs of the rotary catheter.

The cylinder 42 is slidingly disposed in a distal end of a tubularhousing 45 and a ferrule 46, that is press-fitted into the cylinder 42,and is slidingly disposed in an elongated slot 47 defined in the housing45. This allows the cylinder 42 to be slid proximally into the housing(as shown in FIG. 1) or to be slid distally (as shown in FIG. 1 a),displacing the distal end of the flexible tube 13 towards the tip 20.The reduced gap impedes the edge 13 e from engaging with the wall of thevessel 12. While the edge 13 e is preferably rounded or chamfered(please note FIG. 8), the reduced gap further reduces the likelihoodthat the edge 13 e would scrap the wall of the vessel 12 while therotary catheter is advanced distally in a curved section of the vessel.

A flexible conduit 48, the ferrule 46, bores 58 and 59, and seal 43(please note FIG. 1) define together a hydraulic connection between aproximal end of the flexible tube 13 and a suction means in the form ofthe syringe 37. The syringe has a piston 37′ and a cylindrical bodywhich contains thrombolytic drug(s) 39, such as, for example,streptokinase, urokinase, tissue plasminogen activators, also referredto as tPA or rtPA and may also contain anticoagulant and antispasmodicdrugs. Typical thrombolytic drugs are sold by, for example: Genentech,South San Francisco, Calif.; Abbott Laboratories, Green Oaks, Ill.;AstraZeneca, London, UK. The drugs maybe infused into the vessel 12before and/or while the tip is rotating by pushing the piston 37′ intothe syringe's cylindrical body. After the thrombolytic drug and the tiphave cooperatively broken down the obstruction 11 to particles smallenough to be aspirated into the fluid channel defined between the tube13 and the shaft 14, the piston 37′ is pulled out of the cylindricalbody to create a negative pressure in the syringe and aspirate theparticles and fluid in which they are suspended. Representative syringesand vacuum syringes are sold, for example, by Merit Medical Systems,South Jordan, Utah. The relative motion between the flexible tube 13 andthe rotating flexible hollow shaft 14 assists with the aspirationprocess by reducing the frictional resistance that these particlesencounter while moving proximally in the flexible tube 13.

An optional helical wire 94 can be rotatably disposed in bore 59 andaffixed to the flexible hollow shaft portion 16. Upon rotation in thefirst direction, the helical wire 94 automatically assists and regulatesflow of fluid and particles proximally, but when not rotating, thehelical wire 94 resists such flow.

A small direct current motor 50 is housed in a proximal end of thehousing 45, however, other types of electric or air-driven motors, andthe like, can be used. The motor has a tubular output shaft 51 with anoptional electrically insulating coating (not shown). The shaft 51 ispower transmittingly connected at its proximal end to the flexiblehollow shaft portion 16 by a circumferential weld 84 (or, alternatively,by epoxy which is not shown), leaving the length of flexible hollowshaft portion 16 that is nested in a clearance 52 free to bend to alignwith the bore 44′. The increased length of flexible hollow shaft portion16 that participates in the alignment with bore 44′ lowers the stressand strain in the flexible hollow shaft and the frictional forces thatdevelop in the bore 44′ while the flexible hollow shaft portion 16rotates.

FIG. 7 shows the flexible hollow shaft portion 16 connected and bondedto an optional flexible guidewire-liner 60 made of a thin-walled plastictube. The liner may also be secured to the spiraled wire 17 with aspiraled protrusion 92 formed thereon. The spiraled wire can be wound ofone or more wires, also referred to by various manufacturers as strandsor filaments, and it can be constructed in one or more layers of woundwires. Representative single and multi-layered spiraled wires aredisclosed in U.S. Pat. Nos. 4,819,634 and 5,007,896, which areincorporated herein by reference. These earlier patents also show otheroptional spiraled wire designs, such as a jagged spiraled wire shown inFIGS. 3 and 4 of U.S. Pat. No. 5,007,896. Torque-transmitting flexibletubes utilizing a single or multilayered construction, where each layeris made of one or more wires, are also commercially available from AsahiIntecc Co. (with offices at 2500 Red Hill Ave, Santa Ana, Calif., USAand at Aichi-ken, Japan). The common feature of these and other suitablespiraled wires, as the term is used in this application, is their hollowdesign which allows them to slide and rotate over a guidewire, coupledwith an ability to transmit torque from the motor to the tip and theirincreased flexibility, as compared with a non-spiraled or a standardtube of similar internal and external diameters.

Referring back to FIG. 1, a proximal cap 53 houses a seal-set comprisinga seal 54, which seals around the flexible hollow shaft portion 16, anda bushing 55 which secures it in place, and which, like the bushing 44,also serves as a bearing that keeps the flexible hollow shaft portion 16rotating concentrically relative to the seal 54 with the beneficialeffects discussed above in connection with the bushing 44 and the seal43. Housing 45, cylinder 42 and proximal cap 53 are all parts of arotary catheter drive unit. The cap 53 also defines a bore containing anO-ring seal 74 through which a slideable proximal extension in the formof a stepped tube 57 is slidingly disposed. A seal 56 is secured in thestepped tube 57 by a ring 93. To enable insertion of the guidewire 15thru the rotary catheter 10, the stepped tube 57 is pushed distally,causing a proximal end 16′ of the proximal flexible hollow shaft portion16 to cross the seal 56 (please note FIG. 1 d) and enable the guidewireto freely pass thru the seal 56 into, or out of, the proximal end 16′.Upon pulling the stepped tube 57 proximally (please note FIG. 1), theseal 56 closes and seals around the guidewire 15. The seal 56 may bemade of more than one layer of elastomeric material (e.g., two layers offlat silicone rubber), where the distal layer defines a round bore thattightly, yet slidingly, fits around the guidewire 15. The proximal layerhas a slit, or intersecting slits, that seal hermetically in the absenceof the guidewire. The O-ring 74 seals around the stepped tube 57 andfrictionally prevents it from rotating. It also provides the user atactile indication, when it drops into an undercut 95 (please note FIG.1 d), that the stepped tube 57 is in its extended position.

FIG. 1 e is cross-sectional view of a modified slideable proximalextension means in the form of a stepped tube 57′ which defines a borethat provides a bearing support and concentric alignment for theflexible hollow shaft portion 16 with both seals 54 and 56 that arehoused and secured at the distal and proximal ends of the stepped tube57′, respectively. Therefore the bore of bushing 55′ can be enlarged.Stepped tube 57′ is depicted being pushed distally to a position thatenables the guidewire to freely pass distally or proximally thru thedistal end 16′. Upon pulling the stepped tube 57′ proximally, the seal56 closes and, if a guidewire is present, seals around the guidewire. Inthis modified configuration shown in FIG. 1 e, the O-ring 74 providesanti-rotational friction and tactile indication discussed above.

A syringe 62 is hydraulically connected to a proximal end of theflexible hollow shaft portion 16 through a passage 61 and a bore 69defined in the cap 53. The syringe 62 can be used to introduce a fluid,such as saline and drugs, into the flexible hollow shaft portion 16 andinto the liner 60 to prevent blood from entering and clotting in theliner and in the flexible hollow shaft portion 16. Immersion of theproximal end of flexible hollow shaft portion 16 in fluid also preventsair from entering into it when negative pressure prevails in bore 69.The fluid can be supplied by the syringe 62.

Electrical wires 63, 63′, 64 and 64′ connect the motor 50 to a battery65 through a four position switch 66 having a sliding block 68. In theposition shown in FIG. 1, wire 63 is connected to wire 63′ and wire 64is connected to wire 64′, causing the motor to rotate in the firstdirection. When the block 68 is slid upwards (in the direction of arrow68′), the wires are crossed so that wire 63 is connected to wire 64′ andwire 64 is connected wire 63′, causing the motor to rotate in the seconddirection and manually alternating between these positions will causethe motor to rotate back and forth. When a block 67 is slid downwards anelectronic circuit that it contains is interposed between the wires 63and 64 to the wires 63′ and 64′ which automatically causes the motor torotate back and forth (such electronic circuitry which is not shown isfamiliar to the artisan.) In a fourth off-position (not shown) theswitch electrically disconnects the battery from the motor.

Motor 50 has a commutator which can be equipped with a disk varistor toreduce electromagnetic emissions (disk varistors are commerciallyavailable, for example, from TDK Corp., Uniondale, N.Y.) Additionallycapacitors 70, 71 and 72 can be connected to a housing of the motor andwired as shown in FIG. 1.

Ferrite beads (not shown) can be disposed along the wires 63, 64 and63′, 64′ to further reduce the electromagnetic emissions.

A syringe 80 is connected through an introducer 75 to the vessel and canbe used for the introduction of a fluid, such as saline, drugs andradiopaque contrast agent, into the vessel. This fluid can make up forthe volume that is aspirated through the rotary catheter and can be usedto prevent blood from entering the introducer and clotting therein.Alternatively, the syringe 80 can be used to aspirate fluid andparticles out of the vessel, especially while the rotary catheter 10 isnot disposed in the introducer.

In cases where the target obstruction 11 is distant from the puncturesite, a conventional guiding catheter (not shown) may be disposed in theintroducer, to guide the rotary catheter 10 more definitively to theobstruction. Alternatively, a specialized catheter 77 with a toroidalshaped balloon 78 can be used to also seal flow through the vessel andreduce the likelihood of escapement of particles and drugs into theblood stream. The balloon 78 is inflatable and deflatable through achannel 79, defined in a wall of the catheter, by a syringe 81 that isconnected to the channel 79.

A syringe 82 can be used similarly to syringe 80. While syringes 62, 80,81 and 82 are illustrated as being connected directly to various othercomponents, it is understood that they can be connected through flexibleconduits similar to the way syringe 37 is connected through flexibleconduit 48. It can be noted that syringe 82 or syringe 80 can bereplaced with a bag containing a fluid preferably under pressureslightly higher than the patient's blood pressure (not shown).

The guidewire 15 can be a conventional guidewire or it can be equippedwith a distal particle barrier such as a filter (not shown) or a balloon85 that is selectively inflatable through the guidewire 15. Suchguidewires with inflatable balloons are commercially available fromMedtronic Co., Minneapolis, Minn.

Bodily vessels are often curved and bias a catheter that is insertedinto them towards the wall of the vessel. Absent a correction mechanism,such a bias would lead tunneling catheters (i.e., catheters that areintended open an obstruction) to begin tunneling into the obstructionadjacent to the wall, especially in a case of an obstruction thattotally blocks the vessel and cannot be crossed by the guidewire. Insuch a case the rotary catheter 10 can be delivered to the vicinity ofthe obstruction site over the guidewire. The guidewire is then withdrawnproximally past the distal end 36 of the tip. Then, as the tip 20rotates and the crown 27 atraumatically slides against the wall of thevessel, it displaces the distal end 36 of the tip away from the wall(please note FIG. 2.), urging the distal end of the tip to starttunneling away from the wall. After the obstruction has been crossed bythe tip 20, the guidewire can be advanced distally beyond theobstruction, and it can be left inside the vessel after the rotarycatheter has been withdrawn, to provide guidance for subsequentprocedures, such as angioplasty and stenting. It can be understood bythe artisan that this correction mechanism of starting to tunnel awayfrom the vessel's wall would not work if the flexible hollow shaft 14would hypothetically extend distally beyond the tip's distal end 36, asthe tip could not have remotely prevented such a distal extension of theflexible hollow shaft from starting to tunnel adjacent to the wall. Sucha distal extension of the flexible hollow shaft would have alsoincreased the force that would have developed between the rotating crownand the wall of the vessel because, as would be appreciated by theartisan, larger force has to be applied at a mid-point of a beamsupported at both of its ends as compared with the force that has toapplied at the end of a cantilevered beam in order to cause the samedeflection.

Total obstructions may have a hard end layer thus, to enable the tip tostart tunneling, its rounded distal end 36′ can have small tooth orteeth 38 on the part of the distal end of the tip that is further awayfrom the base 26 (please note FIG. 3 a) to reduce the likelihood thatteeth 38 will come into contact with the vessel. To prevent or torelease fibers and the like from wrapping around the flexible hollowshaft or the tip, the flexible hollow shaft and tip can be rotatedbackwards or back and forth in directions 40 and 41. Additionally, inthe event that a large particle becomes lodged in the tube, sliding theflexible tube 13 back and forth relative to the flexible hollow shaft 14can be used to help dislodge it.

The rotary catheter can be introduced into the vessel directly, when thevessel is surgically accessed, or percutaneously through an introducer75, having a sheath 76. The size of an allowable puncture wound 12′(note FIG. 1) in the vessel wall limits the diameter of the sheath 76and an outside diameter 13 od of the flexible tube 13 and the size ofthe inner workings of the catheter and of the tip 20. The flexibletube's internal diameter 13 id and an outside diameter 14 od of theflexible hollow shaft 14 (please note FIG. 8) define between them afluid channel 87. To maximize the cross sectional area of the fluidchannel 87 and the size a particle 87′ that the fluid channel caningest, the sheath 76 as well as the flexible tube 13 are preferablymade of a thin plastic materials and a diameter 14 od of the flexiblehollow shaft is kept substantially smaller than the diameter 13 id. Thedistal end of the flexible hollow shaft 14 extends out of a distal endof the flexible tube 13 and is free to move radially relative to thetube, to one side or another, enabling the channel to ingest particleswhich measure across up to a difference between the diameters 13 id to14 od. It should be noted that, if the distal end of the flexible hollowshaft 14 was mechanically connected to and centered in the distal end ofthe flexible tube 13, for example, by a bearing, the particle size thatcould have theoretically entered the channel 87 would have been reducedby ½ and the particle weight by about ⅞. As the tip rotates, theinteraction of the tip with its surroundings and dynamic forces maycause the distal end of the flexible hollow shaft to randomly moveradially or vibrate relative to the tube, which further discouragesparticles from clogging the fluid channel. Again, by comparison, if thedistal ends of the flexible hollow shaft and the flexible tube weremechanically connected by a bearing or the like, not only could such aconnection interfere with flow through the channel, it would alsodiminish the vibratory unclogging action referred to above. It can alsobe noted that the lack of mechanical connection between the distal endsof the flexible tube 13 and the flexible hollow shaft 14, such as abearing, for example, enhances the overall flexibility of the rotarycatheter by allowing slight longitudinal relative movement between theflexible tube 13 and the flexible hollow shaft 14 when the catheter isbent.

If an oversized particle (which measures across more than the differencebetween the diameters 13 id to 14 od) does enter and wedges in thechannel 87, the spiraled wire 17 (if one is used) is preferably rotatedin a direction that conveys the particle distally to prevent it fromlodging in and clogging the fluid channel. This action can be augmentedby making the cross section of the wire (from which the spiraled wire iswound) with small external ridges 34 (please note FIG. 5). However,particles that are small enough not to become wedged in the channel 87are practically unaffected by the small ridges 34 and are readilyaspirated proximally, eased by the relative rotation of the flexiblehollow shaft 14 to the flexible tube 13, which substantially reduces thefrictional resistance to the movement of particles through the channel87. Thus, the combined relative rotary and radial motion between theflexible hollow shaft and the flexible tube eases the movement ofparticles into and through the fluid channel 87 and impedes particlesfrom clogging it.

It can also be appreciated that enlarging the tip's height 90 to closelyfit through the introducer enhances its effective radius 89 and thecross-sectional area of the tunnel that the tip opens through theobstruction (please note FIG. 3). Increasing the tip height 90 beyondthe flexible tube's internal diameter 13 id (please note FIG. 8) allowsthe flexible tube to be advanced to the tip but not over it. The tip'sheight can be reduced so it is slightly smaller than the internaldiameter 13 id, allowing the flexible tube to be advanced over it andshield it (please note FIGS. 10 a, 10 b). In this shieldedconfiguration, the rotary catheter can aspirate soft obstructions (e.g.,fresh clot) because the tip's narrowed cross-section leaves openpassageways 22′ and 24′ between the tip's sides 22 and 24 to theflexible tube's wall, respectively. As soon as the soft obstructionmaterial enters the passageways 22′ and 24′ and gets in between therotating tip's sides and the flexible tube's wall, the rotating tip andthrombolytic drugs (if used) macerate the clot so that it can be readilyaspirated all the way into the syringe 37. The operation of the tip inthe tube is similar to the tip's operation in a tunnel or a small vesselwhose diameter is close to the tip's height 90.

FIG. 11 shows a further modification, where the flexible tube 13 isterminated along a diagonal line 13′ so that when the cylinder 42 ispartially pulled out of the housing, the flexible tube partially shieldsthe tip. As can be understood by the artisan, the length of the slot 47can be increased to enable the flexible tube to move from a fullyshielding position to a position where the tip and a short section ofthe spiral are exposed. The configuration shown in FIG. 11 enables thetip to be advanced and urged into contact with an asymmetricalobstruction 11′, which is located on one side of the vessel, while theflexible tube distal end acts as a barrier between the tip and anopposite side of the vessel. A radio-opaque marker 19, affixed to thewall of the flexible tube, can be used to assist the user in positioningand orientating the flexible tube relative to the obstruction underX-ray imaging.

FIG. 12 shows a modification of the rotary catheter of FIG. 11, where aflexible tube's distal end 31 resembles a miniaturized scoop of agardening trowel. The scoop shields a certain length of one side of thevessel's wall from the rotating tip while urging the rotating tiptowards an asymmetrical obstruction 11′ located on the opposite side ofthe wall. FIG. 13 shows a scoop 32 with a thicker bottom 33 to urge thetip further towards the obstruction. The elongated shape of scoops 31and 32 shields a length of the obstruction that can be treated withoutrequiring to re-position the scoop in the vessel.

While the present invention has been illustrated with specificembodiments, it should be understood that modifications andsubstitutions may be made within the spirit of the invention and thescope of the claims. For example, to enhance the flexibility of therotary catheter, the spiraled wire 17 can be lengthened and the flexiblehollow shaft portion 16 shortened or vice versa. In such a case of usinga long shaft portion 16, an additional portion of a spiraled wire mayoptionally be attached to the proximal end of the flexible hollow shaftportion 16. Such a configuration may be useful in a long rotary catheterneeded to reach the heart or brain while entering the vasculature at thegroin region. In such an application, the additional proximal spiraledwire portion provides enhanced flexibility at the entry region, whereas,the distal spiraled wire portion 17 provides enhanced flexibility neededin the tortuous coronary vasculature, while the lengthened flexiblehollow shaft portion 16 is sufficiently flexible to be disposed in therelatively intermediate vasculature (e.g., iliac, aorta). Such staggeredconstruction reduces the system's bulk and the longitudinal flexibilityof the flexible hollow shaft 14.

The sides 22 and 24 can be made slightly curved or tilted, from theparallel position depicted in FIG. 3, to form a dihedral angle (pleasenote FIG. 16), so as to increase the passages 22′ and 24′ whilenarrowing the crown, or conversely, they be made so as to increase thecrown to provide a larger bearing area for the tip as it slides over awall of the vessel 13.

The guidewire enables delivering the rotary catheter through tortuousvasculature to remote occlusions and operating it with an enhanceddegree of safety. However, a rotary catheter, according to the presentinvention, is adaptable to occasionally operate with the guidewirewithdrawn proximally into the flexible hollow shaft to address specificclinical scenarios. One such scenario is adapting the rotary catheter tocross total occlusion as was previously discussed. Another scenariorelates to treating large vessels (e.g., blood vessels in the pelvicarea, hemodialysis fistula, aneurysm) with the rotary catheter shown inFIGS. 14-18. FIG. 14 shows a distal end section of the spiraled wire 17that extends out of the distal end of the flexible tube 13 beingstraightened by a guidewire 15 that is disposed through it. However, thedistal end section of the spiraled wire is pre-formed to automaticallyassume a curved shape when the guidewire 15 is withdrawn from it (pleasenote FIG. 17) and to thereby increase the offset of the tip 20. This inturn substantially increases the area within circle 29′ that the tipsweeps (please note FIG. 17), as compared to the area within circle 29(please note FIGS. 14 and 3). It should however be understood that theactual cross section of the tunnel that is opened by the tip will alsobe effected by, for example, the topography and material of thesurrounding vessel and obstruction and the rotational speed of theflexible hollow shaft and tip. Thus, when a larger segment of a vesselhas to be treated, the guidewire can be withdrawn proximally out of thespiraled wire, allowing the pre-formed distal end section of thespiraled wire to automatically assume its pre-formed curved shape shownin FIG. 17 and thereby increase the tip's sweep. Optionally, the usercan gradually withdraw the guidewire to achieve a corresponding gradualcurving of the distal end section of the spiraled wire and conversely,in the absence of the guidewire, the user can reduce the curvature byadvancing the flexible tube as shown in FIG. 1 a. After opening thelarge vessel, the guidewire can be re-advanced distally through the tipto re-assume the configuration shown in FIG. 14 and the guidewire may beleft in the vessel after withdrawing the rotary catheter to facilitatefor follow-up procedure (e.g., angioplasty and/or deployment of astent).

FIG. 16 is cross sectional view of a modified tip 20′, along a plane16-16 marked on FIG. 14. The tip has slightly curved sides and anenhanced effective radius 89 which is achieved by reducing the offset 88and essentially using the spiraled wire as a base 26′.

FIG. 15 shows a further modification of the tip (viewed in the directionof arrow 15′ marked on FIG. 14) where a first side of the tip 103 isinclined by an angle 101 so that it propels fluid and particles of theobstruction proximally when the tip rotates in a first direction.

FIG. 18 shows a further modification of the flexible hollow shaft(viewed in the direction of arrow 18′ marked on FIG. 17) wherein, in theabsence of a guidewire, it also tilts by an angle 102 so that it propelsfluid and particles of the obstruction proximally when it rotates in afirst direction. The line 28′ is a continuation of line 28, whereas line104 is a longitudinal axis of the spiraled wire section that is in thetilted tip.

1. A rotary catheter drive unit containing a motor and a seal-set, anoutput shaft of said motor being power transmittingly connected to aflexible shaft that is rotatably disposed through said seal-set, saidseal-set comprising a bearing and an adjacent seal defining a first anda second concentric bores, respectively, said first bore being slightlylarger than a diameter of said shaft so that it rotatably and accuratelysupports said shaft, said second bore being slightly smaller than saiddiameter so that it seals around said shaft, said bearing aligning saidshaft, so that it is concentric with said second bore, by deflectingsaid shaft to compensate for eccentricity and misalignment of the secondbore relative to said output shaft of said motor.
 2. A rotary catheterdrive unit as in claim 1 containing one seal-set distally relative tosaid motor and a second seal set seal-set proximally relative to saidmotor, wherein said flexible shaft passes through both said seal-setsand said motor.
 3. A rotary catheter drive unit as in claim 2 whereinsaid shaft is hollow, extends out of a proximal end of said housing andis slideable and rotatable over a guidewire, a slideable proximalextension of said housing containing a seal adapted to cross and exposesan open distal end of said hollow shaft when said proximal extension isslid distally and, vice versa said seal adapted to cross said distal endof said hollow shaft when said proximal extension is slid proximally andclose.
 4. A process of manufacturing a seal-set comprising the followingsteps: affixing a bearing having a first bore to a seal material,inserting a drill slightly smaller than a diameter of said bore so thatsaid bore rotatably and accurately supports said drill, rotating andadvancing said drill to cut a second bore in said seal material that isslightly smaller and concentric relative to said first bore.
 5. Aprocess of manufacturing a seal-set wherein said drill is hollow shaftwith a sharp tip.
 6. A process of manufacturing a seal-set wherein saiddrill is a single point cutter.
 7. A process of manufacturing a seal-setwherein said drill is hypodermic needle.